In U.S. Pat. No. 3,908,657, a small, wearable medical pump for fluids is disclosed. Also, wearable pumps which comprise a pressure member adapted for orbital motion about an axis of rotation to pump liquids through flexible tubing are commercially available, and may be worn for either the withdrawal of blood for medical purposes or for the controlled infusion of critical medications which should be administered in very low but constant concentrations on an all-day basis. Accordingly, the patient is able to engage in his normal activities while wearing such a pump.
Such a pump is manufactured by Cormed, Inc. of Middleport, N.Y. The pressure member adated for orbital motion is surrounded by a rigid sleeve, which defines an annular groove in its end. The tubing for pumping is forced into the end groove for operation of the pump.
This, however, provides a substantial disadvantage in that the tubing is difficult to get into the groove and into engagement with the pump head or pressure member without being pushed in by a pointed instrument of some kind. This, in turn, can damage the tubing if not done carefully.
Also, the above-cited miniature pump defines a single side slot, into which the tubing enters and exits from the rigid sleeve which surrounds the pump head. At those times, when the pump head is positioned against the side slot, it is possible for liquids to flow through the tubing in an uncontrolled manner, since the side slot provides a position for the tubing sections to retreat from the pump head, and thereby not be closed by the head as in the normal mode of operation. Particularly, if by chance the pump head is stopped in a position against the slot, flow can take place in a free and uncontrolled manner through the tubing, which is most undesirable, particularly when a critical dosage medicament is being administered.
In accordance with this invention, an improved orbital motion tubing pump is provided, which is preferably miniaturized for wearing, in which the installed tubing is prevented from free flow within its bore in all positions of the pressure member or pump head. Furthermore, means are provided for more convenient installation of the tubing about the pump head in a manner which can be less damaging to the tubing.
Other advantages are also provided by the improved pump of this invention as described below.